Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

No text entered.

Reporting Groups

Description

No Implant Attempt

Subjects who did not undergo an implant attempt of a CRT-P or CRT-D device and were not randomized

Unsuccessful Implants

Subjects who underwent an implant attempt of a CRT-P or CRT-D device but were not successfully implanted

CRT-P: Biventricular Pacing Arm

Subjects who were implanted with a CRT-P device and randomized to receive biventricular pacing

CRT-P: Right Ventricular Pacing Arm

Subjects who were implanted with a CRT-P device and randomized to receive right ventricular pacing

CRT-P: Not Randomized

Subjects successfully implanted with a CRT-P device who were not randomized

CRT-D: Biventricular Pacing Arm

Subjects implanted with a CRT-D device and randomized to receive biventricular pacing

CRT-D: Right Ventricular Pacing Arm

Subjects implanted with a CRT-D device and randomized to receive right ventricular pacing.

CRT-D: Not Randomized

Subjects successfully implanted with a CRT-D device who were not randomized

Mortality, Heart Failure-related Urgent Care Visits, or Significant Increase in Left Ventricular End Systolic Volume Index (LVESVI) [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

All-Cause Mortality or Significant Increase in Left Ventricular End Systolic Volume Index [ Time Frame: Participants were followed for the duration of the study, an average of 39.8 months post-randomization. ]

The endpoint is a subject's change in New York Heart Association Classification (a measure of the degree of heart failure a subject has on a 4 class scale, with NYHA I being the healthiest score and NYHA IV being the sickest score) from randomization to each of four time points: 6 months, 12 months, 18 months, and 24 months post-randomization. The change categories listed will be relative to randomization.

Time Frame

Randomization to 24 Months

Safety Issue

No

Population Description

Explanation of how the number of participants for analysis was determined.
Includes whether analysis was per protocol, intention to treat, or another method.
Also provides relevant details such as imputation technique, as appropriate.

For each time point(e.g. 6 months), only subjects with NYHA assessed at both randomization and that time point were included in the analysis. Those who could not be analyzed at a time point(for reasons such as death, exit,missed visit,or NYHA not assessed at visit) are listed under the "Comparative data not available" category for that time point.

Reporting Groups

Description

Biventricular Pacing Arm

Subjects randomized to receive biventricular pacing

Right Ventricular Pacing Arm

Subjects randomized to receive right ventricular pacing.

Measured Values

Biventricular Pacing Arm

Right Ventricular Pacing Arm

Number of Participants Analyzed
[units: participants]

349

342

Change in New York Heart Association Classification
[units: participants]

6 Months: Improved by 2 classes from randomization

5

3

6 Months: Improved by 1 class from randomization

54

43

6 Months: No change from randomization

200

205

6 Months: Worsened by 1 class from randomization

52

41

6 Months: Worsened by 2 classes from randomization

1

1

6 Months: Comparative data not available

37

49

12 Months:Improved by 2 classes from randomization

4

5

12 Months:Improved by 1 class from randomization

54

34

12 Months: No change from randomization

172

172

12 Months: Worsened by 1 class from randomization

49

64

12 Months:Worsened by 2 classes from randomization

2

3

12 Months: Comparative data not available

68

64

18 Months:Improved by 2 classes from randomization

3

2

18 Months: Improved by 1 class from randomization

43

45

18 Months: No change from randomization

142

141

18 Months: Worsened by 1 class from randomization

50

56

18 Months:Worsened by 2 classes from randomization

4

6

18 Months: Comparative data not available

107

92

24 Months:Improved by 2 classes from randomization

2

3

24 Months: Improved by 1 class from randomization

35

36

24 Months: No change from randomization

135

126

24 Months:Worsened by 1 class from randomization

41

54

24 Months:Worsened by 2 classes from randomization

4

3

24 Months: Comparative data not available

132

120

Statistical Analysis 1 for Change in New York Heart Association Classification

Groups [1]

All groups

Method [2]

Posterior Distribution for Average Rank

P Value [3]

0.591

BiV - RV Difference in Average Rank [4]

0.012

[1]

Additional details about the analysis, such as null hypothesis and power calculation:

Subjects' changes in NYHA classification from randomization to 6 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.

[2]

Other relevant method information, such as adjustments or degrees of freedom:

Additional information, such as whether or not the p-value is adjusted for multiple comparisons and the a priori threshold for statistical significance:

BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability, representing the probability that subjects with biventricular pacing have better outcomes at 6 months, was calculated. A probability ≥0.95 was significant.

[4]

Other relevant estimation information:

Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 2 for Change in New York Heart Association Classification

Groups [1]

All groups

Method [2]

Posterior Distribution for Average Rank

P Value [3]

0.986

BiV - RV Difference in Average Rank [4]

0.126

[1]

Additional details about the analysis, such as null hypothesis and power calculation:

Subjects' changes in NYHA classification from randomization to 12 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.

[2]

Other relevant method information, such as adjustments or degrees of freedom:

Additional information, such as whether or not the p-value is adjusted for multiple comparisons and the a priori threshold for statistical significance:

BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 12 months, was calculated. A probability ≥0.95 was significant.

[4]

Other relevant estimation information:

Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 3 for Change in New York Heart Association Classification

Groups [1]

All groups

Method [2]

Posterior Distribution for Average Rank

P Value [3]

0.726

BiV - RV Difference in Average Rank [4]

0.039

[1]

Additional details about the analysis, such as null hypothesis and power calculation:

Subjects' changes in NYHA classification from randomization to 18 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.

[2]

Other relevant method information, such as adjustments or degrees of freedom:

Additional information, such as whether or not the p-value is adjusted for multiple comparisons and the a priori threshold for statistical significance:

BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 12 months, was calculated. A probability ≥0.95 was significant.

[4]

Other relevant estimation information:

Positive values reflect better outcomes over time in the BiV arm than the RV arm.

Statistical Analysis 4 for Change in New York Heart Association Classification

Groups [1]

All groups

Method [2]

Posterior Distribution for Average Rank

P Value [3]

0.701

BiV - RV Difference in Average Rank [4]

0.035

[1]

Additional details about the analysis, such as null hypothesis and power calculation:

Subjects' changes in NYHA classification from randomization to 24 months were determined. The null hypothesis was that the average change among patients with biventricular pacing is equal to that of patients with right ventricular pacing.

[2]

Other relevant method information, such as adjustments or degrees of freedom:

Additional information, such as whether or not the p-value is adjusted for multiple comparisons and the a priori threshold for statistical significance:

BLOCK HF is a Bayesian study; thus p-values were not used. Instead, a posterior probability,representing the probability that subjects with biventricular pacing have better outcomes at 24 months, was calculated. A probability ≥0.95 was significant.

[4]

Other relevant estimation information:

Positive values reflect better outcomes over time in the BiV arm than the RV arm.